MathOverflow is a question and answer site for professional mathematicians. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Hi, I recently came across the famous Buffon's needle problem (, and there is no doubt that the problem as well as its answer are elegant. However, the problem I have in mind, is slightly modified. The original problem deals with parallel lines separated by fixed distance (say, m). What if there are squares of side m instead of just parallel lines? How will this affect the probability? I scratched my brain over this, but could not come up with anything. Can some genius crack this for me?

Regards, Salil

share|cite|improve this question
Laplace is the genius you require - – dke Aug 8 '10 at 15:32
Great! Thanks! You are genius :-)) – Salil Aug 8 '10 at 15:36
up vote 2 down vote accepted

This is solved in Fifty Challenging Problems in Probability with Solutions, the 1965 book by Frederick Mosteller (Problem #54). A very good book to have around in any case.

share|cite|improve this answer
hmmm... 54th problem in 50 challenging problems ... :-)) Thanks! – Salil Aug 8 '10 at 17:22
Yes, there are 56 in total. The book's at my office, so I can't tell you more than that right now, but I can look up the detailed answer tomorrow if you need me to. – Thierry Zell Aug 8 '10 at 18:03
no no ... I will get the book in my college library. Thank you very much for that reference! – Salil Aug 8 '10 at 18:08

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.